Translation Initiation Factor 3 Families: What Are Their Roles in Regulating Cyanobacterial and Chloroplast Gene Expression?
Overview
Affiliations
Initiation is a key control point for the regulation of translation in prokaryotes and prokaryotic-like translation systems such as those in plant chloroplasts. Genome sequencing and biochemical studies are increasingly demonstrating differences in many aspects of translation between well-studied microbes such as Escherichia coli and lesser studied groups such as cyanobacteria. Analyses of chloroplast translation have revealed its prokaryotic origin but also uncovered many unique aspects that do not exist in E. coli. Recently, a novel form of posttranscriptional regulation by light color was discovered in the filamentous cyanobacterium Fremyella diplosiphon that requires a putative stem-loop and involves the use of two different prokaryotic translation initiation factor 3s (IF3s). Multiple (up to five) putative IF3s have now been found to be encoded in 22 % of sequenced cyanobacterial genomes and 26 % of plant nuclear genomes. The lack of similar light-color regulation of gene expression in most of these species suggests that IF3s play roles in regulating gene expression in response to other environmental and developmental cues. In the plant Arabidopsis, two nuclear-encoded IF3s have been shown to localize to the chloroplasts, and the mRNA levels encoding these vary significantly in certain organ and tissue types and during several phases of development. Collectively, the accumulated data suggest that in about one quarter of photosynthetic prokaryotes and eukaryotes, IF3 gene families are used to regulate gene expression in addition to their traditional roles in translation initiation. Models for how this might be accomplished in prokaryotes versus eukaryotic plastids are presented.
Chloroplast proteostasis: A story of birth, life, and death.
Gao L, Hong Z, Wang Y, Wu G Plant Commun. 2022; 4(1):100424.
PMID: 35964157 PMC: 9860172. DOI: 10.1016/j.xplc.2022.100424.
Transcriptome and metabolome analyses of response of Synechocystis sp. PCC 6803 to methyl viologen.
Hu X, Zhang T, Ji K, Luo K, Wang L, Chen W Appl Microbiol Biotechnol. 2021; 105(21-22):8377-8392.
PMID: 34668984 DOI: 10.1007/s00253-021-11628-w.
Liu S, Zheng L, Jia J, Guo J, Zheng M, Zhao J Front Plant Sci. 2019; 10:295.
PMID: 30915096 PMC: 6423176. DOI: 10.3389/fpls.2019.00295.
Eukaryotic translation initiation factor 3 subunit G promotes human colorectal cancer.
Yang C, Zhang Y, Du W, Cheng H, Li C Am J Transl Res. 2019; 11(2):612-623.
PMID: 30899366 PMC: 6413245.
Zoschke R, Bock R Plant Cell. 2018; 30(4):745-770.
PMID: 29610211 PMC: 5969280. DOI: 10.1105/tpc.18.00016.